Many electrical generators, such as induction generators, are associated with a mechanical energy source, such as wind turbines, internal combustion engines, or any other device capable of producing mechanical movement, to convert at least a portion of the mechanical movement to electric energy.
Electric generators may include a rotor shaft rotatably coupled to the mechanical energy source and associated with a rotor assembly. The rotor assembly may include a rotor that rotates relative to a stator around a rotor rotation axis. The stator may include stator conductors and the rotor may include-rotor conductors. The mechanical energy source may rotate the rotor shaft which may drive the rotor relative to the stator, electrically exciting the rotor conductors to generate magnetic flux. Such electrical generators may use the magnetic flux to transfer power between the stator and the rotor, producing voltage in the stator conductors. The voltage in the stator conductors may be used to provide current for powering electrical devices and/or stored for future use.
Electrical generators may include components configured to transmit the rotational movement from the mechanical energy source to the rotor shaft. Engine-driven induction generators, for example, couple the rotational movement of an engine crankshaft to the rotor shaft of the generator. A flywheel may be coupled to the engine crankshaft via an input gear, such as a crankgear, and may transfer the rotational movement of the crankshaft to a clutch coupled to the flywheel. The rotational movement may be transmitted from the clutch to a gear arrangement coupled to the clutch, which in turn may be transmitted to the rotor shaft of a generator.
A gear train may also be coupled to the crankgear and configured to transmit lubrication oil to components of the generator by driving a lubrication oil supply, such as a oil steering pump, oil implement pump, and/or a powertrain oil scavenge pump. However, the typical configuration of the induction generator may not allow for efficient lubrication of all of the generator components. For example, lubrication oil supplied to the gear train may be blocked by the flywheel and by any resultant windage as the flywheel rotates, preventing adequate amounts of lubrication oil from reaching the clutch and gear arrangement. Furthermore, because lubrication oil may be blocked or dammed by the flywheel, excess lubrication oil may accumulate around the flywheel, and as the flywheel rotates, the lubrication oil may be churned, resulting in aeration and churning losses which contribute to inefficiencies of the generator system.
One attempt to improve the lubrication arrangement of a generator system may include removing the flywheel. An example of such a generator system is described in U.S. Pat. No. 2,864,017 (the '017 patent) to Waltscheff, issued on Dec. 9, 1958. The '017 patent describes an induction motor including a stator supported on a motor housing, an intermediate rotor, and a squirrel cage rotor keyed to a rotor shaft and configured to rotate relative the intermediate rotor and the stator. A series of gears coupled together by an overrunning clutch is coupled to the rotor shaft and transfers torque to the intermediate rotor.
Although the generator system of the '017 patent may expose some components to lubrication oil, it may have limitations. For example, the configuration of the gears and the overrunning clutch may block lubrication oil from reaching the clutch, which may prevent adequate lubrication of the clutch and increase the potential for wear.
The generator system of the present disclosure is directed towards improvements to the existing technology.